Thursday, February 01, 2018

Kevin Laland's view of "modern" evolutionary theory (again)

Kevin Laland has just published another critique of modern evolutionary theory. This one appears in Aeon [Evolution unleashed]. His criticism is based on a naive and outdated view of modern evolutionary biology. That view has been widely criticized in the past but Laland continues to ignore such criticisms [e.g. Kevin Laland's new view of evolution].

Here's how he describes the state of modern evolutionary biology.

If you are not a biologist, you’d be forgiven for being confused about the state of evolutionary science. Modern evolutionary biology dates back to a synthesis that emerged around the 1940s-60s, which married Charles Darwin’s mechanism of natural selection with Gregor Mendel’s discoveries of how genes are inherited. The traditional, and still dominant, view is that adaptations – from the human brain to the peacock’s tail – are fully and satisfactorily explained by natural selection (and subsequent inheritance). Yet as novel ideas flood in from genomics, epigenetics and developmental biology, most evolutionists agree that their field is in flux. Much of the data implies that evolution is more complex than we once assumed.

Count me as one who is confused. I don't believe that modern evolutionary biology is the same as the synthesis from 50 years ago. I think it changed considerably in the late 1960's to incorporate the latest discoveries in population genetics. It expanded to place more emphasis on random genetic drift and Neutral Evolution. Those were significant changes. Modern evolution textbooks are very different from those in the 1960s.

Let's take a look at one of these textbooks. The following quotation is from Evolution (2nd ed.) by Douglas Futuyma (p. 322). This is not the latest edition; it was published in 2009.

In developing the theory of selection so far, we have assumed an efffectively infinite population size. However, in a finite population, allele frequencies are simultaneously affected by both selection and chance. As the movement of an airborne dust particle is affected by both the force of gravity and by random collisions with gas molecules (Brownian movement), so the effective size (Ne) of a population and the strength of selection (s) both affect changes in allele frequencies. The effect of random genetic drift is negligible if selection on a locus is strong relative to the population size—that is, if s is much greater than 1/(4Ne), i.e. if 4Nes>1. Conversely, if s is much less than 1/(4Ne) (that is, if 4Nes<1), selection is so weak that the allele frequencies change mostly by genetic drift: the alleles are nearly neutral. The critical value is 4Nes: genetic drift predominates if selection is weak or the effective population size is small.

The blind worship of natural selection is not evolutionary biology. It is arguably not even science.

The statement in Futuyma's textbook was not the way evolutionary biologists thought about evolution in the heyday of the Modern Synthesis back in the 1950s. This change in our way of thinking about evolution may not have been a "paradigm shift" but it was pretty close.

I want to make two points.

The modern view of evolution is much different that the views of 50 years ago in spite of what Kevin Laland says.

Most of the proponents an Extended Evolutionary Theory (EES) share Laland's out-of-date views on modern evolutionary theory. They missed the revolution that took place 50 years ago.

Douglas Futuyma, and others, made these points repeatedly at the 2016 Royal Society conference on EES [The Extended Evolutionary Synthesis - papers from the Royal Society meeting]. Not only did they explain the changes in our way of thinking about population genetics since the 1960s, they also described other developments over the past 50 years that have been incorporated into modern evolutionary theory and our understanding of the history of life.1

Apparently, Kevin Laland and his EES colleagues weren't paying attention during that part of the meeting.

1. The history of life is not the same as evolutionary theory. Evolution is the underlying process that explains the history of life. Our understanding of developmental biology helps us recognize the particular directions that lineages took over the course of millions of years but evolution still requires changes in the frequencies of alleles in a population and that's what evolutionary theory is mostly about [Replaying life's tape].

11 comments
:

"1. The history of life is not the same as evolutionary theory. Evolution is the underlying process that explains the history of life. Our understanding of developmental biology helps us recognize the particular directions that lineages took over the course of millions of years but evolution still requires changes in the frequencies of alleles in a population and that's what evolutionary theory is mostly about..."

I'm not altogether certain it's truly useful to distinguish plate tectonics from geological history of the continents, or the principles of astrophysics from the history of the universe. Nor for that matter am I altogether certain that the multiplication of species is understandable apart from the separation of populations (which makes it hard to understand what 4Ne might mean.)

But I am altogether certain that looking on from the outside as a layman that whatever paragraphs may be in the textbooks at the beginning acknowledging random genetic drift, by the time it gets out to the mass population, it's all natural selection. From that perspective, these vigorous assaults on every seeming dissent from the consensus serve as defenses of panadaptationism.

Geologists are interested in working out the history of plate movements on Earth. The accuracy of their predictions starts to fall off dramatically beyond one billion years ago. They may even get the history wrong from time to time. It is improved by better data.

The accuracy of the ancient history has very little bearing on the theory of plate tectonics and on the massive amount of evidence that supports it. It’s important to distinguish between the reconstruction of particular and unique events in history and the scientific theories that help explain those events retroactively.

If LaLand's point was to communicate to the profession, he was really stupid to pick Aeon, a popular website. I believe the audience at Aeon is firmly convinced the prevailing opinion of professionals is that natural selection optimizes all traits (usually with the added proviso the gene is the unit of selection, not the organism.)

Massimo Piglucci has been commenting on chapters of Laland. In the latest, Piglucci represents LaLand's thinking on a suitable theory of the evolution of language as follows:

"Kevin proceeds by listing six criteria (and adding a seventh of his own) that a successful theory of language’s origin should meet in order to be further considered (I refer the reader to the chapter itself for more in-depth explanations concerning each criterion):

The theory must account for the honesty of early language. (If words are easy and cost-free, why should anyone believe what others say?)The theory should account for the cooperativeness of early language. (Why should people, early on, have gone out of their way to help others by passing to them valuable information?)The theory should explain how language was adaptive from the onset. (As it is hard to imagine how it could have been a spandrel.)The concepts proposed by the theory should be grounded in reality. (That is, how did words acquire meaning in the first place?)The theory should explain the generality of language. (As opposed to the specificity characteristic of every other animal communication system.)The theory should account for the uniqueness of human language. (Why us and not anyone else?)The theory should explain why communication needed to be learned. (Why is it that language needed to be socially learned and capable of changing rapidly?)"

It is not clear to me that LaLand is a malicious incompetent destroying public understanding of science.

"Evolutionary biology teaches us that in small populations, chance factors dominate and the dynamics of evolving populations are dictated by drift, but as populations get larger, natural selection starts to become more important and advantageous mutations become more likely to propagate."

...and...

"Larger populations typically mean faster rates of biological evolution, due to increases in the numbers of novel mutations, and a stronger effect of natural selection relative to genetic drift."

Kevin knows about genetic drift. However, his proposals are not to do with adding drift to evolutionary theory. Everyone knows that is not needed, including Kevin. They are mostly about adding developmental factors to evolutionary theory. Developmental biology was left out of the modern synthesis. None of the contributors were expert in that field. Development was mostly just modeled as an impenetrable black box, transforming genes and environemnt into phenotypes by some unknown process. Numerous developmental biologists have been sore about this ever since.

Then why are people so angry? Because that undercuts the primacy of DNA sequences, aka genetic determinism?

LaLand's comment that larger populations typically have faster rates of biological evolution identifies optimization by natural selection with evolution. I wasn't aware that the multiplication of species by adaptation via natural selection had been established as *the* cause of multiplication of species. So far as change in frequency of alleles go, I rather that there were many instances where genetic drift was quite important. This is rather more like the situation in pop science where random genetic drift gets an occasional mention, but optimization by natural selection is always the default, and the default is universal.

Laland is too revolutionary for some, and not revolutionary enough for others. Any shift in emphasis towards developmental biologists is likely to result in less grant money for everyone else. Evolutionary theory has long been a controversial topic, people still get hot under the collar about it.

It is generally true that Laland likes to do straw man attacks on modern evolutionary theory, as though it hasn't moved on since the 1940s. The modern synthesis is still having a large stultifying effect though; complaining about its ongoing influence seems legitimate to me.

I never have seen a public portrayal of evolution has having had a revolution/paradigm shift in the last fifty years.They seek to persuade audiences that evolution is true as a Darwinian idea that has stood the test of time. Selectionism on mutation all the way.however as evolutionary speculation is examined its found wanting. So revolutions must keep coming to keep it moving on the road.

If you've never seen any change in evolutionary theory in the past 50 years then you haven't been paying attention. (I'm not surprised at that.) If you think that modern evolutionary biologists believe in "selection on mutation all the way" then you are either very poorly informed or deliberately disingenuous (probably both).

Darwinism is so well established that it is difficult to think of evolution except in terms of desirable characteristics and advantageous genes. New technical developments and new knowledge, such as the sequential analysis of proteins and the deciphering of the genetic code, have made a much closer examination of evolutionary processes possible, and therefore necessary. Patterns of evolutionary change that have been observed at the phenotypic level do not necessary apply at the genotypic and molecular levels. We need new rules in order to understand the patterns and dynamics of molecular evolution.

This is not what I meant. I meant that any presentation to the public , in tv shows,science shows, youtube, magazine articles etc, NEVER says revolutins etc have taken place since Darwin They always say its selection on mutations since darwin.I know there has been important changes in evo theory and learned some here on this forum.Indeed a creationist would make this point and face criticism for changing the history.YES as in the quote you make they did see a need for new rules.A creationist would say, like me, these new rules really mean better ideas because previous ideas are failing under modern research.Thats my point. evolutionary biology keeps having to invent itself as time/research goes forward.yet in the public world this is not preached.

Laurence A. Moran

Larry Moran is a Professor Emeritus in the Department of Biochemistry at the University of Toronto. You can contact him by looking up his email address on the University of Toronto website.

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Quotations

The old argument of design in nature, as given by Paley, which formerly seemed to me to be so conclusive, fails, now that the law of natural selection has been discovered. We can no longer argue that, for instance, the beautiful hinge of a bivalve shell must have been made by an intelligent being, like the hinge of a door by man. There seems to be no more design in the variability of organic beings and in the action of natural selection, than in the course which the wind blows.Charles Darwin (c1880)Although I am fully convinced of the truth of the views given in this volume, I by no means expect to convince experienced naturalists whose minds are stocked with a multitude of facts all viewed, during a long course of years, from a point of view directly opposite to mine. It is so easy to hide our ignorance under such expressions as "plan of creation," "unity of design," etc., and to think that we give an explanation when we only restate a fact. Any one whose disposition leads him to attach more weight to unexplained difficulties than to the explanation of a certain number of facts will certainly reject the theory.

Charles Darwin (1859)Science reveals where religion conceals. Where religion purports to explain, it actually resorts to tautology. To assert that "God did it" is no more than an admission of ignorance dressed deceitfully as an explanation...

Quotations

The world is not inhabited exclusively by fools, and when a subject arouses intense interest, as this one has, something other than semantics is usually at stake.
Stephen Jay Gould (1982)
I have championed contingency, and will continue to do so, because its large realm and legitimate claims have been so poorly attended by evolutionary scientists who cannot discern the beat of this different drummer while their brains and ears remain tuned to only the sounds of general theory.
Stephen Jay Gould (2002) p.1339
The essence of Darwinism lies in its claim that natural selection creates the fit. Variation is ubiquitous and random in direction. It supplies raw material only. Natural selection directs the course of evolutionary change.
Stephen Jay Gould (1977)
Rudyard Kipling asked how the leopard got its spots, the rhino its wrinkled skin. He called his answers "just-so stories." When evolutionists try to explain form and behavior, they also tell just-so stories—and the agent is natural selection. Virtuosity in invention replaces testability as the criterion for acceptance.
Stephen Jay Gould (1980)
Since 'change of gene frequencies in populations' is the 'official' definition of evolution, randomness has transgressed Darwin's border and asserted itself as an agent of evolutionary change.
Stephen Jay Gould (1983) p.335
The first commandment for all versions of NOMA might be summarized by stating: "Thou shalt not mix the magisteria by claiming that God directly ordains important events in the history of nature by special interference knowable only through revelation and not accessible to science." In common parlance, we refer to such special interference as "miracle"—operationally defined as a unique and temporary suspension of natural law to reorder the facts of nature by divine fiat.
Stephen Jay Gould (1999) p.84

Quotations

My own view is that conclusions about the evolution of human behavior should be based on research at least as rigorous as that used in studying nonhuman animals. And if you read the animal behavior journals, you'll see that this requirement sets the bar pretty high, so that many assertions about evolutionary psychology sink without a trace.

Jerry Coyne
Why Evolution Is TrueI once made the remark that two things disappeared in 1990: one was communism, the other was biochemistry and that only one of them should be allowed to come back.

Sydney Brenner
TIBS Dec. 2000
It is naïve to think that if a species' environment changes the species must adapt or else become extinct.... Just as a changed environment need not set in motion selection for new adaptations, new adaptations may evolve in an unchanging environment if new mutations arise that are superior to any pre-existing variations

Douglas Futuyma
One of the most frightening things in the Western world, and in this country in particular, is the number of people who believe in things that are scientifically false. If someone tells me that the earth is less than 10,000 years old, in my opinion he should see a psychiatrist.

Francis Crick
There will be no difficulty in computers being adapted to biology. There will be luddites. But they will be buried.

Sydney Brenner
An atheist before Darwin could have said, following Hume: 'I have no explanation for complex biological design. All I know is that God isn't a good explanation, so we must wait and hope that somebody comes up with a better one.' I can't help feeling that such a position, though logically sound, would have left one feeling pretty unsatisfied, and that although atheism might have been logically tenable before Darwin, Darwin made it possible to be an intellectually fulfilled atheist

Richard Dawkins
Another curious aspect of the theory of evolution is that everybody thinks he understand it. I mean philosophers, social scientists, and so on. While in fact very few people understand it, actually as it stands, even as it stood when Darwin expressed it, and even less as we now may be able to understand it in biology.

Jacques Monod
The false view of evolution as a process of global optimizing has been applied literally by engineers who, taken in by a mistaken metaphor, have attempted to find globally optimal solutions to design problems by writing programs that model evolution by natural selection.